Clinical delineation and localization to chromosome 9p13.3-p12 of a unique dominant disorder in four families: hereditary inclusion body myopathy, Paget disease of bone, and frontotemporal dementia.

Autosomal dominant myopathy, Paget disease of bone, and dementia constitute a unique disorder (MIM 605382). Here we describe the clinical, biochemical, radiological, and pathological characteristics of 49 affected (23 male, 26 female) individuals from four unrelated United States families. Among these affected individuals 90% have myopathy, 43% have Paget disease of bone, and 37% have premature frontotemporal dementia. EMG shows myopathic changes and muscle biopsy reveals nonspecific myopathic changes or blue-rimmed vacuoles. After candidate loci were excluded, a genome-wide screen in the large Illinois family showed linkage to chromosome 9 (maximum LOD score 3.64 with marker D9S301). Linkage analysis with a high density of chromosome 9 markers generated a maximum two-point LOD score of 9.29 for D9S1791, with a maximum multipoint LOD score of 12.24 between D9S304 and D9S1788. Subsequent evaluation of three additional families demonstrating similar clinical characteristics confirmed this locus, refined the critical region, and further delineated clinical features of this unique disorder. Hence, autosomal dominant inclusion body myopathy (HIBM), Paget disease of bone (PDB), and frontotemporal dementia (FTD) localizes to a 1.08-6.46 cM critical interval on 9p13.3-12 in the region of autosomal recessive IBM2.

A brief cognitive test battery to differentiate Alzheimer's disease and frontotemporal dementia.

OBJECTIVES: To validate a simple bedside test battery designed to detect mild dementia and differentiate AD from frontotemporal dementia (FTD). METHODS: Addenbrooke's Cognitive Examination (ACE) is a 100-point test battery that assesses six cognitive domains. Of 210 new patients attending a memory clinic, 139 fulfilled inclusion criteria and comprised dementia (n = 115) and nondementia (n = 24) groups. The composite and the component scores on the ACE for the two groups were compared with those of 127 age- and education-matched controls. Norms and the probability of diagnosing dementia at different prevalence rates were calculated. To evaluate the ACE's ability to differentiate early AD from FTD, scores of the cases diagnosed with dementia with a Clinical Dementia Rating < or = 1 (AD = 56, FTD = 24, others = 20) were compared. RESULTS: Two cut-off values for the ACE composite score (88 and 83) were of optimal utility depending on the target population. The ACE had high reliability, construct validity, and sensitivity (93%, using 88 as cut-off). Using the lower cut-off of 83, the ACE had a higher sensitivity (82%) and predictive value than the Mini-Mental State Examination for a wide range of dementia prevalence. The ACE differentiated AD from FTD, and the VLOM ratio (derived using component scores: [verbal fluency + language]/[orientation + memory]) of <2.2 for FTD and >3.2 for AD was highly discriminating. CONCLUSION: The ACE is a brief and reliable bedside instrument for early detection of dementia, and offers a simple objective index to differentiate AD and FTD in mildly demented patients.

Dementia and aphasia in motor neuron disease: an underrecognised association?

OBJECTIVES: To determine the prevalence and nature of global cognitive dysfunction and language deficits in an unselected population based cohort of patients with motor neuron disease (MND). METHODS: A battery of neuropsychological and language tests was administered to patients presenting consecutively over a 3 year period to a regional neurology service with a new diagnosis of sporadic motor neuron disease. RESULTS: The 18 patients could be divided on the basis of their performance into three groups: Three patients were demented and had impaired language function (group 1); two non-demented patients had an aphasic syndrome characterised by word finding difficulties and anomia (group 2). Major cognitive deficits were therefore found in five of the 18 patients (28%). The remaining 13 performed normally on the test battery apart from decreased verbal fluency (group 3). CONCLUSIONS: The prevalence of cognitive impairment in MND in this population based study of an unselected cohort was higher than has been previously reported. Language deficits, especially anomia, may be relatively frequent in the MND population. Aphasia in MND may be masked by dysarthria and missed if not specifically examined.